The rotor of an electrostatic MEMS micromotor, which is ratchet-driven, must be guided precisely in rotation in order to make it possible for the ratchets to work correctly. A standard manner is to form an integrated fixed axle, produced at the same time as the rotor and its boring. Such an example is described in the document WO 2004/081695.
The boring-axis radial clearance of a rotor with an integrated axle cannot be less than the minimum cut achievable by deep plasma etching technology termed DRIE (Deep Reactive Ion Etching), generally 5 microns for 80 microns of thickness. On the other hand, the lateral friction of silicon on silicon is increased (μ=0.4).
The invention aims to resolve these problems in a simple and economical manner.